This is a prospective non-randomised Phase I/II study with patients recruited to escalated dose cohorts. Escalated dose to the iGTV (internal gross tumour volume), with 60 Gy to the conventional PTV (planning target volume), will be delivered to successive cohorts of participants (6-12 participants/cohort) until the maximum tolerated oesophageal dose is determined. The minimum dose will be 60 Gy delivered via intensity modulated radiation therapy (IMRT) or volume modulated arc therapy (VMAT), planned on an Average Intensity Projection (AVIP) dataset.